implement std::hash for css::uno::Reference and rtl::Reference

The declaration in BarChart.cxx is particularly suspicious, because it
was using a < for the KeyEqual template parameter.
Been there since:
commit b2c3233e5f267b5d244d722a94424a3b224b3314
Date:   Thu Dec 21 20:08:33 2017 +0900
chart2: suspend/resume setting rects dirty for 3D shapes

comphelper::OInterfaceCompare is no longer necessary

Change-Id: I8278c4a3d9113a18570ca237cd05d553ec8f3975
Reviewed-on: https://gerrit.libreoffice.org/71537
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

1 files changed, 24 insertions, 0 deletions

diff --git a/include/rtl/ref.hxx b/include/rtl/ref.hxx
index 437f7a34fc05..73c03ff7657d 100644
--- a/include/rtl/ref.hxx
+++ b/include/rtl/ref.hxx
@@ -23,6 +23,8 @@
 #include "sal/config.h"
 
 #include <cassert>
+#include <cstddef>
+#include <functional>
 
 #include "sal/types.h"
 
@@ -250,6 +252,28 @@ public:
 
 } // namespace rtl
 
+#if defined LIBO_INTERNAL_ONLY
+namespace std
+{
+
+/// @cond INTERNAL
+/**
+  Make rtl::Reference hashable by default for use in STL containers.
+
+  @since LibreOffice 6.3
+*/
+template<typename T>
+struct hash<::rtl::Reference<T>>
+{
+    std::size_t operator()(::rtl::Reference<T> const & s) const
+    { return std::size_t(s.get()); }
+};
+/// @endcond
+
+}
+
+#endif
+
 #endif /* ! INCLUDED_RTL_REF_HXX */
 
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